DE112020004323T5 - Aftertreatment system including preheating oxidation catalyst - Google Patents

Abstract

An aftertreatment system for treating an exhaust gas includes an exhaust gas line, a preheating oxidation catalyst, a primary oxidation catalyst disposed downstream of the preheating oxidation catalyst, and a selective catalytic reduction system disposed in the exhaust gas line downstream of the primary oxidation catalyst. A controller is configured to determine the temperature of an exhaust gas at an inlet of the selective catalytic reduction system. In response to the temperature being below a threshold temperature, the controller generates a hydrocarbon induction signal configured to cause hydrocarbons to be inducted into or upstream of the preheating oxidation catalyst to raise the temperature of the exhaust gas to above increase the threshold temperature.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the provisional U.S. Application No. 62/900,220 , filed Friday, September 13, 2019, the entire disclosure of which is hereby incorporated herein by reference.

TECHNICAL AREA

The present disclosure relates generally to the field of aftertreatment systems, and more particularly to systems and methods for controlling temperature in an aftertreatment system.

STATE OF THE ART

Exhaust aftertreatment systems are used to receive and treat the exhaust gases produced by internal combustion engines. In general, exhaust aftertreatment systems include any number of different components for reducing the level of harmful exhaust emissions in the exhaust. For example, certain exhaust aftertreatment systems for diesel-powered internal combustion engines include a selective catalytic reduction (SCR) system that includes a catalyst formulated to reduce NO _x (NO and NO ₂ in a specified fraction) in the presence of ammonia (NH ₃ ) into harmless nitrogen gas (N ₂ ) and water vapor (H ₂ O). Generally, in such aftertreatment systems, an exhaust reductant (e.g., a diesel exhaust fluid such as urea) is injected into the SCR system to provide a source of ammonia and mixed with the exhaust to partially reduce the NOx _gases . The exhaust gas reduction byproducts are then flowed to the catalyst included in the SCR system to break down substantially all of the _NOx gases into relatively harmless byproducts that are emitted from the aftertreatment system.

In certain situations, for example when starting an engine from cold, the temperature of the exhaust gas may be too low to effectively decompose the reductant and produce ammonia. In addition, the SCR temperature of the SCR system may be below an optimal operating temperature of the SCR system. This can result in the catalytic conversion efficiency of the SCR system being lower than the desired catalytic conversion efficiency, resulting in a higher amount of _NOx gases in the exhaust gases being emitted into the environment after passing through the aftertreatment system, which is undesirable .

EXECUTIVE SUMMARY

The embodiments described herein relate generally to systems and methods for heating an exhaust gas flowing into an aftertreatment system, and more particularly to aftertreatment systems that include a preheating oxidation catalyst that combusts hydrocarbons introduced therein when the temperature of the exhaust gas entering the aftertreatment system is below a threshold temperature so as to increase the temperature of the exhaust gas.

In some embodiments, an aftertreatment system for treating exhaust gas produced by an engine includes: an exhaust line configured to receive the exhaust gas; a preheating oxidation catalyst; a primary oxidation catalyst located downstream of the preheating oxidation catalyst; an SCR system arranged in the exhaust pipe downstream of the primary oxidation catalyst; and a controller. The controller is configured to: determine a temperature of the exhaust gas at an inlet of the SCR system and generate a command to introduce hydrocarbons in response to the temperature of the exhaust gas at the inlet of the SCR system being below a threshold temperature, configured to cause hydrocarbons to be introduced into the preheating oxidation catalyst or into the exhaust gas upstream of the preheating oxidation catalyst. The preheating oxidation catalyst is configured to catalyze combustion of the injected hydrocarbons to increase the temperature of the exhaust gas above the threshold temperature.

In some embodiments, the controller is configured to cause the hydrocarbons to be introduced in response to a temperature of the exhaust gas being greater than the preheating oxidation catalyst light-off temperature.

In some embodiments, the aftertreatment system further includes a heater operably coupled to the preheating oxidation catalyst, wherein the controller is configured to selectively activate the heater when the temperature of the exhaust gas is less than the light-off temperature of the preheating oxidation catalyst.

In some embodiments, the controller is further configured to: in response to the temperature of the exhaust gas reaching a primary oxidation catalyst light-off temperature but still being below the threshold temperature, inject hydrocarbons into the primary oxidation catalyst or into the exhaust gas between the preheating oxidation catalyst and the primary oxidation catalyst.

In some embodiments, the controller is further configured to: stop introducing the hydrocarbons in response to the temperature of the SCR system increasing to or above an upper threshold temperature that is greater than the threshold temperature.

In some embodiments, the SCR system includes an upstream catalyst and a downstream catalyst located downstream of the upstream catalyst. In some embodiments, the upstream catalyst comprises an FeZ catalyst. In some embodiments, the downstream catalyst comprises a CuZ catalyst.

In some embodiments, the hydrocarbons are introduced via a hydrocarbon introduction assembly included in the aftertreatment system and/or via the engine. In some embodiments, the preheating oxidation catalyst has a light-off temperature that is lower than the light-off temperature of the primary oxidation catalyst.

In some embodiments, the aftertreatment system further includes: a first hydrocarbon injector positioned upstream of the preheating oxidation catalyst; and a second hydrocarbon injector positioned between the preheating oxidation catalyst and the primary oxidation catalyst.

In some embodiments, a method for controlling the operations of an aftertreatment system that includes a preheating oxidation catalyst, a primary oxidation catalyst downstream of the primary oxidation catalyst, and an SCR system downstream of the primary oxidation catalyst, the method comprising: determining, by a controller, a temperature the exhaust gas at an inlet of the SCR system; and in response to the temperature of the exhaust gas at the inlet of the SCR system being below a threshold temperature, generating, by the controller, a hydrocarbon injection command configured to cause hydrocarbons to flow into the preheating oxidation catalyst or are introduced into the exhaust gas upstream of the preheating oxidation catalyst, wherein the preheating oxidation catalyst is configured to catalyze combustion of the injected hydrocarbons to increase a temperature of the exhaust gas to be above the threshold temperature.

In some embodiments, the controller causes the introduction of the hydrocarbons when the temperature of the exhaust gas is greater than the light-off temperature of the preheating oxidation catalyst.

In some embodiments, the aftertreatment system further comprises a heater operably coupled to the preheating oxidation catalyst, and the method further comprises: causing the controller to activate the heater in response to the temperature of the exhaust gas being lower than the light-off temperature of the preheating oxidation catalyst.

In some embodiments, the method further comprises: in response to the temperature of the exhaust gas reaching a light-off temperature of the primary oxidation catalyst but still being below the threshold temperature, causing the introduction of the hydrocarbons, through the controller, into the primary oxidation catalyst or into the Exhaust gas between the preheating oxidation catalyst and the primary oxidation catalyst.

In some embodiments, the method further comprises: in response to the temperature of the selective catalytic reduction system increasing to be equal to or greater than an upper threshold temperature that is greater than the threshold temperature, the controller discontinuing the introduction of the hydrocarbons .

In some embodiments, a controller for controlling operations of an aftertreatment system, including a preheating oxidation catalyst, a primary oxidation catalyst downstream of the primary oxidation catalyst, and an SCR system downstream of the primary oxidation catalyst, is configured to: a temperature of the exhaust gas at an inlet of the SCR system; and in response to the temperature of the exhaust gas at the inlet of the SCR system being below a threshold temperature, generating a hydrocarbon injection command configured to cause hydrocarbons to inject into the front warming oxidation catalyst or in the exhaust gas upstream of the prewarming oxidation catalyst, wherein the prewarming oxidation catalyst is configured to catalyze combustion of the injected hydrocarbons to increase a temperature of the exhaust gas to be above the threshold temperature.

In some embodiments, the controller generates the command to inject hydrocarbons in response to a temperature of the exhaust gas being above the preheating oxidation catalyst light-off temperature.

In some embodiments, the aftertreatment system further includes a heater operably coupled to the preheating oxidation catalyst, and wherein the controller is further configured to: the heater in response to the temperature of the exhaust gas being lower than the light-off temperature of the preheating oxidation catalyst , selectively activated.

In some embodiments, the controller is further configured to, in response to the temperature of the exhaust gas reaching a primary oxidation catalyst light-off temperature but still being below the threshold temperature, reducing the introduction of the hydrocarbons into the primary oxidation catalyst or into the exhaust gas between the causes preheating oxidation catalyst and the primary oxidation catalyst.

It should be understood that any combination of the above concepts and other concepts discussed in more detail below (provided that such concepts are not mutually incompatible) may be considered part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter listed at the end of this disclosure are considered part of the inventive subject matter disclosed herein.

character list

• 1 ist eine schematische Veranschaulichung eines Nachbehandlungssystems, das einen vorwärmenden Oxidationskatalysator einschließt, gemäß einer Ausführungsform.
• 2 sind Diagramme, welche Temperaturen eines Abgases zeigen, das von einem Motor beim Kaltstart ausgestoßen wurde, das ohne Vorwärmen des Abgases (Baseline SM) und das mit Vorwärmen durch einen vorwärmenden Oxidationskatalysator (ccDOC + SM) zu einem nachgelagerten SCR-System strömt.
• 3 sind Diagramme, welche Temperaturen eines Abgases zeigen, das von einem Motor beim Warmstart ausgestoßen wurde, das ohne Vorwärmen des Abgases (Baseline SM) und das mit Vorwärmen durch einen vorwärmenden Oxidationskatalysator (ccDOC + SM) zu einem nachgelagerten SCR-System strömt.
• 4 sind Diagramme, die den Anstieg der SCR-Einlasstemperatur im Laufe der Zeit durch ein Abgas zeigen, das von einem Motor beim Kaltstart ausgestoßen wurde, ohne dass das Abgas vorgewärmt wurde (A1), und mit dem Abgas, das durch den vorwärmenden Oxidationskatalysator vorgewärmt wurde (A5).
• 5 sind Diagramme, die den Anstieg der SCR-Einlasstemperatur im Laufe der Zeit durch ein Abgas zeigen, das von einem Motor beim Warmstart ausgestoßen wurde, ohne dass das Abgas vorgewärmt wurde (A1), und mit dem Abgas, das durch den vorwärmenden Oxidationskatalysator vorgewärmt wurde (A5).
• 6 ist ein Balkendiagramm, das die NO_x-Menge zeigt, die von einem Endrohr eines Nachbehandlungssystems (ATS) emittiert wird, das den vorwärmenden Oxidationskatalysator nicht einschließt (herkömmliches ATS), eines Nachbehandlungssystems, das einen vorwärmenden Oxidationskatalysator einschließt (ccDOC + herkömmliches ATS), und eines Nachbehandlungssystems, das den vorwärmenden Oxidationskatalysator und ein Heizgerät einschließt, das betriebsfähig mit dem Oxidationskatalysator gekoppelt ist (2 kW Heizgerät + ccDOC + herkömmliches ATS).
• 7 ist ein schematisches Flussdiagramm eines Verfahrens zum Steuern der Temperatur in einem Nachbehandlungssystem gemäß einer Ausführungsform.

The foregoing and other features of the present disclosure will become more apparent from the following description and appended claims when read in conjunction with the accompanying drawings. With the understanding that these drawings represent only some embodiments according to the disclosure and therefore should not be considered as limiting the scope of the disclosure, the disclosure will be described in more detail using the accompanying drawings.

• 1 12 is a schematic illustration of an aftertreatment system including a preheating oxidation catalyst, according to one embodiment.
• 2 are graphs showing temperatures of an exhaust gas emitted from an engine at cold start, flowing without exhaust gas preheating (Baseline SM) and with preheating through a preheating oxidation catalyst (ccDOC + SM) to a downstream SCR system.
• 3 are graphs showing temperatures of an exhaust gas emitted from an engine at hot start, flowing without exhaust gas preheating (Baseline SM) and with preheating through a preheating oxidation catalyst (ccDOC + SM) to a downstream SCR system.
• 4 are graphs showing the increase in SCR inlet temperature over time by an exhaust gas emitted from an engine at cold start without the exhaust gas being preheated (A1) and with the exhaust gas preheated by the preheating oxidation catalyst (A5).
• 5 are graphs showing the increase in SCR inlet temperature over time by an exhaust gas emitted from an engine at hot start without the exhaust gas being preheated (A1) and with the exhaust gas preheated by the preheating oxidation catalyst (A5).
• 6 Figure 12 is a bar graph showing the amount of NOx emitted from a tailpipe of an aftertreatment system (ATS) not including the preheated oxidation catalyst (conventional ATS), an aftertreatment system including a preheated oxidation catalyst ( _ccDOC + conventional ATS), and an aftertreatment system that includes the preheating oxidation catalyst and a heater operably coupled to the oxidation catalyst (2 kW heater + ccDOC + conventional ATS).
• 7 12 is a schematic flow diagram of a method for controlling temperature in an aftertreatment system according to one embodiment.

Throughout the following detailed description, reference is made to the accompanying drawings. In the drawings, similar symbols typically identify similar components unless the context otherwise pretends. The illustrative embodiments described in the detailed description, drawings, and claims are not to be taken in a limiting sense. Other implementations may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein. It should be understood that the aspects of the present disclosure, as generally described herein and illustrated in the figures, may be arranged, substituted, combined, and configured in many different configurations, all of which are expressly contemplated and incorporated by reference in this disclosure .

DETAILED DESCRIPTION

The embodiments described herein relate generally to systems and methods for heating an exhaust gas flowing into an aftertreatment system, and more particularly to aftertreatment systems that include a preheating oxidation catalyst that combusts hydrocarbons introduced therein when the temperature of the exhaust gas entering the aftertreatment system is below a threshold temperature so as to increase the temperature of the exhaust gas.

_{Aftertreatment} systems that can achieve ultra-low NOx emissions at the aftertreatment system tailpipe (e.g., greater than _50-75 % reduction in NOx gases) are desirable to meet future diesel engine emissions regulations. One of the major bottlenecks in meeting ultra-low NO _x regulations is the inability of conventional SCR systems to convert NO _x at low temperatures, for example temperatures below 175 degrees Celsius. Due to the low activity of conventional SCR systems at low temperatures, considerable _NOx emissions are released at the tailpipe during a cold start, ie when the exhaust gas of an engine is emitted which is started after a certain period of time in a cold state. More than 50-75% _tailpipe NOx reduction compared to current _{tailpipe NOx} regulations is required to meet ultra-low NOx regulations. However, future regulations will also require lower greenhouse gas (e.g. CO ₂ ) emissions.

Various solutions have been proposed to meet ultra-low _NOx requirements and to accommodate the regeneration of filters (e.g., diesel particulate filters) included in aftertreatment systems. This includes, for example, increasing the engine's external temperatures by increasing the amount of fuel burned in the engine (e.g. by running the engine under rich conditions) to heat up the SCR system more quickly and the To increase the efficiency of NO _x conversion. However, this approach decreases fuel efficiency as more fuel has to be burned in the engine to increase the engine exhaust gas temperature, and also increases CO ₂ emissions.

Another approach involves reducing the thermal mass upstream of the SCR system, which may require different architectures than traditional aftertreatment systems. For example, one approach includes removing the upstream filter and positioning the filter after the SCR system. However, this type of architecture has significant disadvantages in terms of filter regeneration intervals, as placing the SCR system upstream of the filter consumes all _NOx , resulting in minimal to no passive soot oxidation. This leads to frequent soot-related regeneration events. Similarly, other architectures that reduce thermal mass in front of the SCR system typically have significant trade-offs that make them difficult to implement. An external heater can be operably coupled to the SCR system to increase its temperature during engine cranking, but this increases power consumption and complexity of the aftertreatment system.

The main goal of these approaches is to achieve ultra-low tailpipe _NOx values (eg, more than 75% _NOx reduction) during a transient cycle, ie when the exhaust gas temperature is lower is than an optimal operating temperature of the SCR system (eg, less than about 175 degrees Celsius). This low temperature exhaust gas is generally emitted from the engine during the first 400-500 seconds of the Federal Test Procedure (FTP) cold and warm-up cycles and results in about 90-95% of an initial amount of NO _x being trapped in the exhaust gas that enters the aftertreatment system are emitted to the environment. The reason for this is that the SCR system is not active at these temperatures and the reducing agent cannot be dosed in the first few seconds of the cold and warm cycle due to the low temperature. However, as described earlier herein, conventional approaches suffer from several disadvantages that limit their feasibility.

Various embodiments of the systems and methods described herein may provide one or more benefits including, for example: (1) increasing the temperature of an exhaust gas entering an SCR system to an optimal temperature for operation of the SCR system during the transient phase by a preheated oxidation catalyst associated with the SCR system is arranged upstream; (2) providing less thermal mass upstream of the SCR system; (3) Allowing for easy integration into existing aftertreatment systems; and (4) providing ultra-low _NOx emissions at a tailpipe of the aftertreatment system during the transient period.

1 10 is a schematic illustration of an aftertreatment system 100 according to one embodiment. The aftertreatment system 100 is configured to receive an exhaust gas (e.g., a diesel exhaust gas) from an engine 10 and decompose components of the exhaust gas such as _NOx gases, CO, and so on. The aftertreatment system 100 includes a reductant storage tank 110, a reductant delivery assembly 112, an SCR system 150, a primary oxidation catalyst 120, a preheating oxidation catalyst 180, and a controller 170, and may optionally also include a hydrocarbon delivery assembly 114, a filter 130, a mixer 140, and an ammonia - Include oxidation catalyst 160.

The engine 10 may be an internal combustion engine, such as a diesel engine, a gasoline engine, a natural gas engine, a biodiesel engine, a dual fuel engine, an alcohol engine, an E85 engine, or any other suitable internal combustion engine.

The reductant storage tank 110 contains a reductant formulated to enable the reduction of exhaust constituents (eg, _NOx gases) by a catalyst included in the SCR system 150 . In embodiments where the exhaust is a diesel exhaust, the reductant may include a diesel exhaust fluid (DEF) that provides an ammonia source. Suitable DEFs include urea, aqueous urea solutions, or any other DEF (e.g., the DEF available under the trade name ADBLUE®). In certain embodiments, the reductant includes an aqueous urea solution having 32.5% urea and 67.5% deionized water. In other embodiments, the reducing agent includes an aqueous urea solution having 40% urea and 60% deionized water.

The reductant delivery assembly 112 is fluidly connected to the reductant storage tank 110 and configured to receive the reductant from the reductant storage tank 110 and introduce the reductant into the exhaust flowing through the aftertreatment system 100, for example, upstream of the SCR system 150.

The SCR system 150 is configured to receive and treat the exhaust (eg, a diesel exhaust) flowing through the SCR system 150 in the presence of ammonia. The aftertreatment system 100 includes an exhaust manifold 101 that defines an exhaust gas flow path for propagating the exhaust gas. The SCR system 150 is positioned within the exhaust pipe 101 . In some embodiments, the exhaust line 101 includes an inlet pipe 102 positioned upstream of the SCR system 150 and configured to receive exhaust gas from the engine 10 and communicate the exhaust gas to the SCR system 150 . The exhaust line 101 may also include an outlet tube 104 for expelling the treated exhaust gas to atmosphere. The outlet pipe 104 can be connected to a tail pipe. In some embodiments, the SCR system 150 may include an upstream catalyst 152 (e.g., an FeZ catalyst) and a downstream catalyst 154 (e.g., a CuZ catalyst).

A primary oxidation catalyst 120 (eg, a diesel oxidation catalyst) may be disposed upstream of the SCR system 150 and configured to oxidize unburned hydrocarbons that may be present in the exhaust. A filter 130 (eg, a diesel particulate filter) may be located downstream of the primary oxidation catalyst 120 and upstream of the SCR system 150 and is configured to filter particulate matter (eg, soot, ash, etc.) trapped in the exhaust. In some embodiments, the hydrocarbon induction assembly 114 is configured to inject hydrocarbons into the exhaust upstream of the primary oxidation catalyst 120 . The primary oxidation catalyst 120 is configured to catalyze the combustion of the hydrocarbons to increase the temperature of the exhaust gas to a temperature sufficient to regenerate the filter 130 and/or the SCR system 150.

In some embodiments, a mixer 140 may be located upstream of the SCR system 150 and configured to allow mixing of the reductant with the exhaust before the reductant flows into the SCR system 150 . In some embodiments, the ammonia oxidation catalyst 160 may be located downstream of the SCR system 150 and configured to treat any ammonia that may be produced by the SCR system 150 has not been consumed, ie it prevents ammonia slip.

As already described herein, the temperature of the exhaust gas in transient phases, e.g. B. during cold or warm engine cycles, below a threshold temperature, for example below about 175 degrees Celsius. At such low temperatures, the reductant may not fully decompose and the SCR system 150 may operate at a temperature where the catalytic conversion efficiency of the SCR system 150 is significantly lower than its optimal catalytic conversion efficiency. This can result in higher NO _x emissions in the exhaust gases being expelled from the aftertreatment system 100 .

To increase the temperature of the exhaust gas during such transient periods, the aftertreatment system 100 also includes a preheating oxidation catalyst 180 located upstream of the primary oxidation catalyst 120 . The preheating oxidation catalyst 180 may include a coated catalyst substrate, including, for example, a metal, cordierite, metal foam, or other substrate. In some embodiments, the preheating oxidation catalyst 180 may be located in the intake pipe 102 . In some embodiments, the hydrocarbon induction assembly 114 is configured to selectively inject hydrocarbons into the preheating oxidation catalyst 180 or into the exhaust gas upstream of the preheating oxidation catalyst 180 .

In some embodiments, aftertreatment system 100 may include a first hydrocarbon (HC) injector 116a located upstream of preheating oxidation catalyst 180, and may optionally also include a second HC injector 116b located downstream of preheating oxidation catalyst 180 and primary oxidation catalyst 120 is arranged upstream. In some embodiments, the hydrocarbon induction assembly 114 may be configured to inject hydrocarbons into the exhaust upstream of the preheating oxidation catalyst 180 via the first HC injector 116a. The hydrocarbon introduction assembly 114 may introduce hydrocarbons into the preheating oxidation catalyst or into the exhaust gas upstream of the preheating oxidation catalyst 180 when the temperature of the exhaust gas at an inlet of the SCR system 150 (SCR inlet temperature) measured by an SCR temperature sensor 107 falls below a threshold temperature (eg, below about 175 degrees Celsius). In other embodiments, the hydrocarbons may be provided via engine 10 .

The preheating oxidation catalyst 180 is configured to generate heat from the combustion of the hydrocarbons, which heats the exhaust gas and, in turn, the downstream SCR system 150 . This increases the catalytic conversion efficiency of the SCR system 150 and results in ultra-low _NOx emissions even during engine 10 transient phases (e.g., cold start or warm start). The preheating oxidation catalyst 180 is specifically designed to burn hydrocarbons at lower temperatures and generate heat. When hydrocarbons (e.g., diesel fuel) are injected across the preheat oxidation catalyst 180, the preheat oxidation catalyst 180 oxidizes those hydrocarbons and generates heat. This heat, in turn, may heat downstream exhaust aftertreatment components, such as the SCR system 150, more quickly. The preheat oxidation catalyst 180 is primarily used to generate the heat to warm up the downstream SCR system 150 more quickly and is designed to generate e.g. B. when the filter 130 is filled with soot, provides only limited heat generation.

In some embodiments, a turbocharger 184 may be installed upstream of the aftertreatment system 100 such that exhaust gas flows through the turbocharger 184 before passing through the preheating oxidation catalyst 180 and flowing to the SCR system 150 . The preheating oxidation catalyst 180 offers the advantage of lower thermal mass compared to the primary oxidation catalyst 120 . Because the preheating oxidation catalyst 180 is located closer to the turbocharger 184, heat loss through the downcomer can be avoided and it can be specifically designed to generate heat from the reaction of hydrocarbons. The preheated oxidation catalyst 180 also has a lower light-off temperature (i.e., the temperature at which the preheated oxidation catalyst 180 can ignite the hydrocarbons) than the primary oxidation catalyst 120 so that the preheated oxidation catalyst 180 can ignite the hydrocarbons at a lower temperature, for example at Temperatures less than about 175 degrees Celsius.

In some embodiments, a heater 182 (eg, a 2 kW heater) may be operably coupled to the preheating oxidation catalyst 180 and configured to provide the preheating selectively heats the warming oxidation catalyst 180, for example when the temperature of the exhaust gas is lower than the light-off temperature of the preheating oxidation catalyst 180. The use of the heater 182 provides the further advantage that the hydrocarbons can be dosed earlier, which allows for better control of _NOx emissions allows. The use of the preheated oxidation catalyst 180 is preferable to combusting the fuel in the engine 10 because combusting the fuel over the preheated oxidation catalyst 180 is typically more thermally efficient than combusting the fuel in the engine 10 . In other embodiments, preheating oxidation catalyst 180 may include an electrically heated catalyst having, for example, electrical windings configured to heat the oxidation catalyst.

A temperature sensor 103 may be disposed within intake manifold 102 and is configured to measure the temperature of exhaust gas discharged from engine 10 , for example after it has passed through turbocharger 184 . The SCR temperature sensor 107 may be located upstream of the SCR system 150, for example between the SCR system 150 and the primary oxidation catalyst 120, and configured to measure the SCR inlet temperature. The controller 170 is operatively connected to the hydrocarbon induction assembly 114 , the temperature sensor 103 and the SCR temperature sensor 107 . In some embodiments, the controller 170 may also be operatively coupled to the reductant injection assembly 112 . Controller 170 may include one or more components configured to perform the controller 170 operations described herein. For example, controller 170 may include a processor (e.g., microprocessor, programmable logic controller (PLC) chip, ASIC chip, or other suitable processor) that is capable of communicating with memory (e.g., RAM, ROM or other non-transitory computer-readable medium). The processor can be configured to execute instructions, algorithms, commands, or other programs stored in memory. Controller 170 may also include one or more modules or circuitry configured to perform the various operations of controller 170 .

The controller 170 is configured to determine the SCR inlet temperature of the exhaust gas flowing into the aftertreatment system 100 . For example, the controller 170 may receive a temperature signal from the SCR temperature sensor 107 and determine the SCR inlet temperature. In response to the temperature being below the threshold temperature, the controller 170 may generate a hydrocarbon induction command configured to cause hydrocarbons to be introduced into the prewarming oxidation catalyst 180 or into the exhaust gas upstream of the prewarming oxidation catalyst 180 will. For example, the controller 170 may instruct the hydrocarbon introduction assembly 114 to introduce hydrocarbons into the preheating oxidation catalyst 180 or into the exhaust gas upstream of the preheating oxidation catalyst 180, such as via the first HC injector 116a, or command the engine 10 to introduce hydrocarbons into the exhaust gas that is in the preheating oxidation catalyst 180 enters. In some embodiments, the controller 170 is configured to introduce the hydrocarbons into the preheating oxidation catalyst 180 or into the exhaust gas upstream of the preheating oxidation catalyst 180 in response to the temperature of the exhaust gas being greater than the light-off temperature of the preheating oxidation catalyst 180.

In some embodiments where the heater 182 is operatively coupled to the preheating oxidation catalyst 180, the controller 170 may be operatively coupled to the heater 182 and configured to turn on the heater 182 in response to the temperature of the exhaust gas being below the light-off temperature of the preheating oxidation catalyst 180 is selectively activated to raise the temperature of the preheating oxidation catalyst 180 to the light-off temperature.

The preheating of the exhaust gas by the preheating oxidation catalyst 180 also heats the primary oxidation catalyst 120. Once the temperature of the exhaust gas reaches a light-off temperature of the primary oxidation catalyst 120, the controller 170 may also command the hydrocarbon induction assembly 114 to upstream hydrocarbons into the primary oxidation catalyst 120 or into the exhaust of the primary oxidation catalyst 120 to bring. The primary oxidation catalyst 120 then burns the hydrocarbons, which leads to a further increase in the temperature of the exhaust gas and thus the SCR system 150 .

Furthermore, in some embodiments, the aftertreatment system 100 can also have the first HC injector 116a, which is arranged upstream of the preheating oxidation catalyst 180, and the second HC injector 116b, which is arranged downstream of the preheating oxidation catalyst 180 is arranged include. Hydrocarbons for heating the exhaust may be introduced from the engine 10 or via the hydrocarbon introduction assembly 114 via the first HC injector 116a, and in some embodiments via the second HC injector 116b as well. Additionally, hydrocarbons for combustion at the primary oxidation catalyst 120 may be introduced by the hydrocarbon introduction assembly 114 via the second HC injector 116b. Any suitable hydrocarbons can be added to the exhaust, such as diesel, gasoline, propane, natural gas, etc. The introduction of hydrocarbons via the engine 10 or through the first HC injector 116a, which is upstream of the preheating oxidation catalyst 180, and through the second HC -Injector 116b can be independent or interdependent.

In some embodiments where hydrocarbons may be introduced both upstream and downstream of the preheating oxidation catalyst 180, the controller 170 may be configured to initiate hydrocarbon introduction in response to the SCR inlet temperature being below the threshold temperature. In such embodiments, the preheating oxidation catalyst 180 may be located closer to the turbocharger 184 than the primary oxidation catalyst 120 . In some embodiments, hydrocarbons may be introduced both upstream and downstream of the preheating oxidation catalyst 180 (eg, via the first and second HC injectors 116a/b). In other embodiments, hydrocarbons may only be introduced upstream of the preheating oxidation catalyst 180 (e.g., via the first HC injector 116a), such as when the exhaust gas temperature is greater than the light-off temperature of the preheating oxidation catalyst 180. In still other embodiments, the hydrocarbons may only be introduced downstream of the preheating oxidation catalyst 180 (e.g. via the second HC injector 116b), for example when exhaust gas temperature is higher than the light-off temperature of the primary oxidation catalyst 120. In some embodiments, the controller 170 may be configured to limit the supply of fuel stops once the SCR inlet temperature is equal to or greater than an upper threshold temperature (eg, greater than about 150 degrees Celsius to 500 degrees Celsius).

As previously described herein, the hydrocarbon introduction upstream of the preheating oxidation catalyst 180 (e.g., via the engine 10 or through the first HC injector 116a through the hydrocarbon introduction assembly 114) may be based on the light-off temperature of the preheating oxidation catalyst 180 . The light-off temperature of the preheating oxidation catalyst 180 may be a temperature at which approximately 50% of the hydrocarbons introduced into the exhaust gas are combusted by the preheating oxidation catalyst 180 . In some embodiments, the light-off temperature of preheating oxidation catalyst 180 may range from about 125 degrees Celsius to about 300 degrees Celsius. In some embodiments, controller 170 is configured to initiate hydrocarbon injection upstream of or on preheating oxidation catalyst 180 in response to a preheating oxidation catalyst 180 inlet temperature (e.g., measured by temperature sensor 103) or preheating bed temperature Oxidation catalyst 180 is equal to or greater than the light-off temperature of the preheating oxidation catalyst 180.

In some embodiments, the controller 170 is configured to adjust hydrocarbon injection downstream of the preheating oxidation catalyst 180 and upstream of the primary oxidation catalyst 120 (e.g., through the second HC injector 116b via the hydrocarbon injection assembly 114) based on a primary oxidation catalyst light-off temperature 120 initiates. For example, the controller 170 may instruct the hydrocarbon induction assembly 114 to inject hydrocarbons into the exhaust when the primary oxidation catalyst inlet temperature (eg, as measured by a primary oxidation catalyst inlet temperature sensor 109) or the bed temperature of the primary oxidation catalyst 120 is equal to or greater than is the light-off temperature of the primary oxidation catalyst 120 . The light-off temperature of the primary oxidation catalyst 120 is a temperature at which the primary oxidation catalyst 120 is able to burn approximately 50% of the hydrocarbons introduced into the exhaust gas. In some embodiments, the light-off temperature of the primary oxidation catalyst 120 may range from about 150 degrees Celsius to about 400 degrees Celsius.

As described earlier herein, in response to a temperature of the preheating oxidation catalyst 180 being below its light-off temperature, the controller 170 may be configured to activate the heater 182 so as to heat the preheating oxidation catalyst 180 . In some embodiments, the controller 170 may be configured to activate the heater 182 when the SCR inlet temperature is below the threshold temperature. The controller 170 can be configured to disable the heater 182 when the SCR On let temperature is equal to or greater than the upper threshold temperature.

In some embodiments where the aftertreatment system 100 is configured to inject hydrocarbons both upstream of the preheating oxidation catalyst 180 (e.g., via the engine 10 or the first HC injector 116a) and downstream of the preheating oxidation catalyst 180 (e.g via the second HC injector 116b) and also includes the heater 182, the controller 170 may be configured to selectively and independently: (a) introduce hydrocarbons upstream of the preheating oxidation catalyst 180; (b) introducing hydrocarbons downstream of the preheating oxidation catalyst 180; and/or (c) activate the heater 182 when the SCR inlet temperature is below the temperature threshold. In other embodiments, the introduction of the hydrocarbons upstream and/or downstream of the preheating oxidation catalyst 180 and the activation of the heater 182 may be performed in a dependent manner.

Activation or deactivation of each of the above items may be based on one or more of the following factors: SCR inlet temperature, preheating oxidation catalyst inlet or bed temperature, primary oxidation catalyst inlet or bed temperature, flow rate of the exhaust gas, oxygen concentration in the exhaust gas, etc. In some In embodiments, heater 182 may be activated without introducing hydrocarbons. In other embodiments, the hydrocarbons may be introduced upstream or downstream of the preheating oxidation catalyst 180 without activating the heater 182 .

In some embodiments, the aftertreatment system 100 may only be configured to induct hydrocarbons upstream of the preheating oxidation catalyst 180, for example via the engine 10 or the first HC injector 116a through the hydrocarbon induction assembly 114 and the second HC injector 116b is excluded. In such embodiments, the preheating oxidation catalyst 180 may be located closer to the primary oxidation catalyst 120 than to the turbocharger 184 . The controller 170 may be configured to introduce hydrocarbons upstream of the preheating oxidation catalyst 180 and/or activate the heater 182 independently or dependently on each other when the SCR inlet temperature is below the threshold temperature. The controller 170 may also be configured to independently or dependently disable the heater 182 and/or hydrocarbon injection when the SCR inlet temperature is equal to or greater than the upper threshold temperature. The activation or deactivation of each of the above elements may be based on one or more of the following factors: SCR inlet temperature, preheating oxidation catalyst inlet or bed temperature, primary oxidation catalyst inlet or bed temperature, flow rate of the exhaust gas, oxygen concentration in the exhaust gas, etc.

The introduction of the hydrocarbons upstream of the preheating oxidation catalyst 180 may be based on the light-off temperature of the preheating oxidation catalyst 180, as previously described herein. In some embodiments, the heater 182 can be activated without introducing hydrocarbons. In other embodiments, the hydrocarbons may be introduced upstream or downstream of the preheating oxidation catalyst 180 without activating the heater 182 .

In some embodiments, the controller 170 may be configured to receive an SCR input temperature signal from the SCR temperature sensor 107 and determine the SCR input temperature therefrom. The controller 170 may be configured to stop introducing hydrocarbons into the preheating oxidation catalyst 180 or into the exhaust gas upstream of the preheating oxidation catalyst 180 once the temperature of the SCR system is equal to or greater than the upper threshold temperature, for example about 250 Centigrade. The controller 170 may restart hydrocarbon injection in response to the temperature of the SCR system falling below the upper threshold temperature. Once the temperature of the exhaust and/or the SCR system 150 is equal to or greater than the threshold temperature, the controller 170 may instruct the reductant delivery assembly 112 to introduce the reductant into the exhaust.

In some embodiments where hydrocarbons are introduced by engine 10 or hydrocarbon introduction assembly 114 upstream of heater 182 , preheating oxidation catalyst 180 may be eliminated and exhaust preheating may be performed solely by heater 182 . In such embodiments, the controller 170 may be configured to activate the heater 182 and/or the introduction of hydrocarbons into the exhaust upstream of the heater 182 independently or in Interdependence caused when the SCR inlet temperature is below the temperature threshold. Activation or deactivation of each of the above items may be based on one or more of the following factors: SCR inlet temperature, preheating oxidation catalyst inlet or bed temperature, primary oxidation catalyst inlet or bed temperature, flow rate of the exhaust gas, oxygen concentration in the exhaust gas, etc. In some In embodiments, heater 182 may be activated without introducing hydrocarbons. In other embodiments, the hydrocarbons may be introduced upstream or downstream of the preheating oxidation catalyst 180 without activating the heater 182 . The hydrocarbon introduction may be based on the light-off temperature of the primary oxidation catalyst 120, as previously described herein. The heater 182 may allow for faster hydrocarbon injection.

2-6 12 are graphs obtained through various simulations of increasing the exhaust gas temperature of exhaust gas flowing through an aftertreatment system by preheating the exhaust gas with a preheating oxidation catalyst. For example shows 2 Graphs showing temperatures of an exhaust gas emitted by an engine at cold start, flowing without exhaust gas preheating (Baseline SM) and with preheating through a preheating oxidation catalyst (ccDOC + SM) to a downstream SCR system. Temperatures are measured at an outlet of a filter included in the aftertreatment system. The temperature of the SCR system can rise significantly during a cold FTP cycle, such as out 2 emerges.

3 12 are graphs showing temperatures of an exhaust gas emitted from an engine at hot start, flowing without exhaust gas preheating (Baseline SM) and with preheating through a preheating oxidation catalyst (ccDOC + SM) to a downstream SCR system. Temperatures are measured at the outlet of a filter (e.g., by the SCR temperature sensor 107) included in the aftertreatment system. The temperature of the SCR system can increase significantly during a warm FTP cycle, such as out 3 emerges.

The criteria chosen for hydrocarbon dosing can have a significant impact on the temperature profile of the downstream aftertreatment components. The pre-heating oxidation catalyst enables optimal hydrocarbon dosing, which enables faster warm-up of the SCR system with lower CO ₂ emissions. An example of a slightly more optimized hydrocarbon dosing strategy and how it improves the SCR inlet temperature of an SCR system as well as the performance of the SCR system is given in 4 and 5 shown.

4 are graphs showing the increase in SCR inlet temperature over time by an exhaust gas emitted from an engine at cold start without the exhaust gas being preheated (A1) and with the exhaust gas preheated by the preheating oxidation catalyst (A5). 5 are graphs showing the increase in SCR inlet temperature over time by an exhaust gas emitted from an engine at hot start without the exhaust gas being preheated (A1) and with the exhaust gas preheated by the preheating oxidation catalyst (A5). How out 4 and 5 As can be seen, the optimized hydrocarbon dosing strategy used for the A5 aftertreatment architecture (preheating oxidation catalyst architecture) specifically targets the low temperature range and helps to warm up the SCR system faster. Further, hydrocarbon dosing is stopped when the SCR inlet temperature is equal to or greater than about 250 degrees Celsius, thereby minimizing the amount of CO ₂ emitted to the environment.

Combustion of hydrocarbons over the preheat oxidation catalyst in the preheat oxidation catalyst aftertreatment system (A5) allows for faster warm-up and better temperatures for the downstream SCR system. The percentage of time spent above the DEF dosing threshold temperature is higher with A5 than with the base architecture A1, which does not include the prewarming oxidation catalyst. In addition, higher SCR bed temperatures result in improved SCR- _NOx conversion efficiency in A5 compared to A1.

6 12 is a bar graph showing the amount of NOx emitted from a tailpipe of an aftertreatment system that does not include the preheated oxidation catalyst (conventional ATS), an aftertreatment system that includes a preheated oxidation catalyst ( _ccDOC + conventional ATS), and an aftertreatment system , which includes the preheated oxidation catalyst and a heater operatively coupled to the preheated oxidation catalyst (2 kW heater + ccDOC + conventional ATS).

As in 6 As can be seen, the ccDOC + conventional ATS architecture with the optimized hydrocarbon dosing process results in a more than 60% reduction in tailpipe NO _x reduction compared to conventional ATS. In addition, the installation of the heater further improves system performance and reduces system NO _x emissions. The heat generated by the Preheating Oxidation Catalyst ( _ccDOC ) not only contributes to NOx reduction via the SCR system, but can also aid in the oxidation of soot in the filter, making the system more passive and reducing the need for high-temperature active regeneration. Therefore, the aftertreatment system architecture with ccDOC can enable ultra-low NO _x levels at the system exit with minimal fuel losses, as well as assisted passive soot combustion.

7 12 is a schematic flow diagram of an example method 200 for controlling the temperature in the aftertreatment system 100, which includes the SCR system 150, the primary oxidation catalyst 120, and the primary oxidation catalyst 120 upstream of the oxidation catalyst 180, and also the heater operatively coupled to the preheating oxidation catalyst 180 182 may include. While method 200 is described in relation to aftertreatment system 100, it may be used with any aftertreatment system that includes a preheating oxidation catalyst.

The method 200 at 202 includes determining a temperature of the exhaust gas entering the aftertreatment system. For example, the controller 170 may determine the SCR inlet temperature based on a temperature signal from the SCR temperature sensor 107 . At 204, the controller 170 determines whether the SCR inlet temperature is below the threshold temperature. The method 200 returns to operation 202 in response to determining that the exhaust gas temperature is above the threshold temperature (204:NO).

However, if the SCR inlet temperature is determined to be below the threshold temperature (204:YES), in some embodiments the method 200 includes the controller 170 determining at 206 whether the exhaust gas temperature is equal to or greater than the light-off temperature of the preheating oxidation catalyst 180 is. In response to the controller 170 determining that the temperature of the exhaust gas is above the light-off temperature (206:YES), the method 200 proceeds to operation 210 and the controller 170 causes hydrocarbons to flow into the preheating oxidation catalyst 180 or into the Exhaust may be introduced upstream of the preheating oxidation catalyst 180 (eg, via the engine 10 or by the first HC injector 116a via the hydrocarbon introduction assembly 114). However, if the controller 170 determines that the temperature of the exhaust gas is below the light-off temperature (206:NO), the controller 170 instructs 208 the heater 182 to heat the preheating oxidation catalyst 180, for example, until the temperature of the exhaust gas is equal to or greater than is the light-off temperature of the preheating oxidation catalyst 180 . The method 200 then proceeds to operation 210 as previously described herein. The controller 170 may then instruct the reductant delivery assembly 112 to introduce a reductant into the exhaust flowing through the aftertreatment system 100 .

At 212, the controller 170 determines whether the SCR inlet temperature (eg, based on a temperature signal from the SCR temperature sensor 107) is equal to or greater than an upper threshold temperature (eg, equal to or greater than about 250 degrees Celsius ). In response to the SCR inlet temperature being below the upper threshold temperature (212:NO), the method 200 returns to operation 210 and the controller 170 suspends the introduction of hydrocarbons into the preheating oxidation catalyst 180 or into the exhaust gas upstream of the preheating Oxidation catalyst 180 continued. However, if the controller 170 determines that the SCR inlet temperature is equal to or greater than the upper threshold temperature (212:YES), the controller 170 stops introducing the hydrocarbons at 214 and the method 200 returns to operation 202.

It should be noted that the term "example" as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations and/or illustrations of possible embodiments (and that such a term is not necessarily intended to be indicative). that such embodiments are exceptional or outstanding examples).

As used herein, the term "coupled" and the like means the direct or indirect joining of two elements together. Such a connection may be stationary (e.g., permanent) or moveable (e.g., removable or detachable). Such a connection can be achieved in that the two elements or the two elements and any other intermediate elements are integrally formed as a unitary body with each other, or in that the two elements or the two elements and any further intermediate elements are attached to each other.

As used herein, the term "about" generally means plus or minus 10% of the specified value. For example, "about 0.5" would include the values 0.45 and 0.55, "about 10" would include 9 through 11, "about 1000" would include 900 through 1100.

It is important to note that the structure and arrangement of the various exemplary embodiments are for the purpose of illustration only. Although only some embodiments have been described in detail in this disclosure, upon reading this disclosure, those skilled in the art will readily recognize that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements , use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Additionally, it is understood that features from one embodiment disclosed herein may be combined with features from other embodiments disclosed herein, as is known to a person skilled in the art. Other substitutions, modifications, changes, and omissions may also be made in the construction, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

Although this specification contains many specific embodiment details, these should not be construed as limiting the scope of any of the inventions or the claims, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. In contrast, various features described in the context of a single implementation may be implemented in multiple implementations separately or in any suitable sub-combination. In addition, although features may be described above as operative in certain combinations and may also be initially claimed as such, one or more features of a claimed combination may in some cases be excluded from the combination and the claimed combination may extend to a sub-combination or variation of a sub-combination.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US62900220 [0001]

Claims (20)

An aftertreatment system for treating an exhaust gas produced by an engine, the aftertreatment system comprising: an exhaust line configured to receive the exhaust gas; a preheating oxidation catalyst; a primary oxidation catalyst disposed downstream of the primary oxidation catalyst; a selective catalytic reduction system disposed in the exhaust passage downstream of the primary oxidation catalyst; and a controller configured to: determining a temperature of the exhaust gas at an inlet of the selective catalytic reduction system, and in response to the temperature of the exhaust gas at the inlet of the selective catalytic reduction system being below a threshold temperature, generating a hydrocarbon injection command configured to cause hydrocarbons to be introduced into the prewarming oxidation catalyst or into the exhaust gas upstream of the preheating oxidation catalyst is introduced, wherein the preheating oxidation catalyst is configured to catalyze combustion of the injected hydrocarbons such that the temperature of the exhaust gas is increased above the threshold temperature. aftertreatment system claim 1 wherein the controller is configured to cause the hydrocarbons to be introduced in response to the temperature of the exhaust gas being greater than the preheating oxidation catalyst light-off temperature. aftertreatment system claim 2 , further comprising a heater operatively coupled to the preheating oxidation catalyst, wherein the controller is configured to selectively activate the heater when the temperature of the exhaust gas is less than the light-off temperature of the preheating oxidation catalyst. aftertreatment system claim 1 , wherein the controller is further configured to: in response to the temperature of the exhaust gas reaching a light-off temperature of the primary oxidation catalyst but still being below the threshold temperature, introducing the hydrocarbons into the primary oxidation catalyst or into the exhaust gas between the preheating oxidation catalyst and the primary oxidation catalyst. aftertreatment system claim 1 wherein the controller is further configured to: stop introducing the hydrocarbons in response to the temperature of the selective catalytic reduction system increasing to or above an upper threshold temperature that is greater than the threshold temperature. aftertreatment system claim 1 wherein the selective catalytic reduction system comprises an upstream catalyst and a downstream catalyst downstream of the upstream catalyst. aftertreatment system claim 6 , wherein the upstream catalyst comprises an FeZ catalyst. aftertreatment system claim 6 , wherein the downstream catalyst comprises a CuZ catalyst. aftertreatment system claim 1 wherein the hydrocarbons are introduced via a hydrocarbon introduction assembly included in the aftertreatment system and/or via the engine. aftertreatment system claim 1 , wherein the preheating oxidation catalyst has a light-off temperature that is lower than a light-off temperature of the primary oxidation catalyst. aftertreatment system claim 1 , further comprising: a first hydrocarbon injector positioned upstream of the preheating oxidation catalyst; and a second hydrocarbon injector positioned between the preheating oxidation catalyst and the primary oxidation catalyst. A method for controlling the operations of an aftertreatment system comprising a prewarming oxidation catalyst, a primary oxidation catalyst downstream of the prewarming oxidation catalyst, and a selective catalytic reduction system downstream of the primary oxidation catalyst, the method comprising: determining, by a controller, a temperature of the exhaust gas at an inlet of the selective catalytic reduction system; and in response to the temperature of the exhaust gas at the inlet of the selective catalytic reduction system being below a threshold temperature, generating, by the controller, a command to introduce hydrocarbons so configured is adapted to cause hydrocarbons to be introduced into the preheating oxidation catalyst or into the exhaust gas upstream of the preheating oxidation catalyst, the preheating oxidation catalyst being configured to catalyze the combustion of the introduced hydrocarbons such that the temperature of the exhaust gas is increased so that that it is above the threshold temperature. procedure after claim 12 wherein the introduction of the hydrocarbons is effected by the controller when the temperature of the exhaust gas is higher than the light-off temperature of the preheating oxidation catalyst. procedure after Claim 13 wherein the aftertreatment system further comprises a heater operatively coupled to the preheating oxidation catalyst, and wherein the method further comprises: causing the controller to activate the heater in response to the temperature of the exhaust gas being less than the light-off temperature of the preheating oxidation catalyst . procedure after claim 12 , further comprising: in response to the temperature of the exhaust gas reaching a light-off temperature of the primary oxidation catalyst but still being below the threshold temperature, causing the introduction of the hydrocarbons, through the controller, into the primary oxidation catalyst or into the exhaust gas between the preheating oxidation catalyst and the primary oxidation catalyst. procedure after claim 12 , further comprising: in response to the temperature of the selective catalytic reduction system increasing to or above an upper threshold temperature greater than the threshold temperature, stopping, by the controller, introduction of the hydrocarbons. A controller for controlling operations of an aftertreatment system that includes a prewarming oxidation catalyst, a primary oxidation catalyst downstream of the prewarming oxidation catalyst, and a selective catalytic reduction system downstream of the primary oxidation catalyst, the controller being configured to: determining a temperature of the exhaust gas at an inlet of the selective catalytic reduction system; and in response to the temperature of the exhaust gas at the inlet of the selective catalytic reduction system being below a threshold temperature, generating a hydrocarbon injection command configured to cause hydrocarbons to be introduced into the preheating oxidation catalyst or into the exhaust gas upstream of the preheating oxidation catalyst are introduced, wherein the preheating oxidation catalyst is configured to catalyze the combustion of the introduced hydrocarbons such that the temperature of the exhaust gas is increased such that it is above the threshold temperature. control after Claim 17 wherein the controller generates the hydrocarbon induction command in response to a temperature of the exhaust gas being above the preheating oxidation catalyst light-off temperature. control after Claim 18 wherein the aftertreatment system further comprises a heater operatively coupled to the preheating oxidation catalyst, and wherein the controller is further configured to: selectively activate the heater in response to the temperature of the exhaust gas being below the light-off temperature of the preheating oxidation catalyst. control after Claim 18 , further configured to: in response to the temperature of the exhaust gas reaching a light-off temperature of the primary oxidation catalyst but still being below the threshold temperature, causing the introduction of the hydrocarbons into the primary oxidation catalyst or into the exhaust gas between the preheating oxidation catalyst and the primary oxidation catalyst .

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